The biggest issue for me is the UI. I actually seriously dislike it. I used ESET, BitDefender, Avira and Avast in the past and the UI is way better in those programs.
The protection is quite decent, but when I run certain new apps, the program can get in the way quickly. I know, I can disable things... But I try to not configure the program how I would use it since I test out the program if I would recommend it to clients or not. And most of my clients aren't that tech savy or don't know a lot about computers, so yeah.